The present technology relates to a technical field of a zoom lens and an image pickup apparatus, and more particularly to a technical field of a zoom lens and an image pickup apparatus wherein both of increase in magnification and angle are achieved and besides reduction in diameter is achieved.
In recent years, small-sized image pickup apparatuses such as a video camera and a digital camera for consumer use have been widespread also for home use.
For such small-sized image pickup apparatus, a high-performance wide-angle zoom lens is demanded wherein the entire lens system is reduced in size and increased in magnification.
Generally, as a zoom lens used for a video camera, an inner focus type zoom lens is available wherein lens groups other than a first lens group disposed most on the object side are moved to carry out focusing. It is known that, in such an inner focus type zoom lens, the entire lens system can be reduced in size readily and besides an imaging performance suitable for an image pickup device having a large number of pixels is obtained.
In an inner focus type zoom lens, a four-group type inner zoom lens system is frequently used wherein a first lens group and a third lens group are fixed while a second lens group is moved in the direction of an optical axis to principally carry out zooming. Further, a fourth lens group is moved in the direction of the optical axis to carry out correction of the focal position by zooming and focusing. An inner focus type zoom lens is disclosed, for example, in Japanese Patent Laid-Open No. 2009-175648 (hereinafter referred to as Patent Document 1).